ncd/extra/address_utils.h: add NCDVal_HasOnlyContinuousStrings() assertions
ncd/extra/address_utils.h: add NCDVal_HasOnlyContinuousStrings() assertions

DavidCox1979/badvpn,DavidCox1979/badvpn,DavidCox1979/badvpn,DavidCox1979/badvpn,DavidCox1979/badvpn